Conveyor dishwasher

ABSTRACT

A conveyor dishwasher includes at least one wash zone and at least one final rinse zone, wherein the at least one wash zone is designed to spray wash liquid, wherein the wash liquid is, at least proportionally, liquid which has already been used for final rinsing in the at least one final rinse zone and to which a wash chemical is added in a metered manner or is fresh water to which a wash chemical is added in a metered manner, wherein the conveyor dishwasher has a metering pump for adding the wash chemical in a metered manner to the liquid to be sprayed in the at least one wash zone, and wherein a controller is associated with the conveyor dishwasher in order to actuate the metering pump and a wash pump or final rinse pump of the dishwasher.

TECHNICAL FIELD

The present invention relates generally to the field of commercial dishwashing and, more particularly, to a conveyor dishwasher comprising at least one wash zone and at least one final rinse zone.

BACKGROUND

A typical conveyor dishwasher has at least one main wash zone and at least one final rinse zone that is downstream of the at least one main wash zone as seen in the conveying direction of the washware. The at least one final rinse zone can be embodied as a pump final rinse zone and/or as a fresh water final rinse zone and serves to spray pure fresh water, to which optionally a rinse aid chemical is added, onto the washware to be treated (fresh water final rinse zone) or to spray recirculated fresh water, to which optionally a rinse aid chemical is added in a metered manner, onto the washware to be treated (pump final rinse zone).

By contrast, in the at least one main wash zone of the conveyor dishwasher, wash liquid is sprayed onto the washware to be treated. The wash liquid is either the liquid which has already been used for final rinsing in the at least one final rinse zone and to which a corresponding wash chemical (detergent) is added in a metered manner or is fresh water to which a wash chemical (detergent) is added in a metered manner.

Optionally, the conveyor dishwasher can also have at least one prewash zone upstream of the at least one main wash zone as seen in the conveying direction of the washware.

Conveyor dishwashers of the type in question here are also referred to as multi-tank machines in the field of commercial dishwashing. In these machines, the washware to be treated is conveyed through the individual treatment zones of the conveyor dishwasher with the aid of a conveyor apparatus. The conveyor dishwashers in question here are in particular commercial conveyor dishwashers and can be configured as flight-type dishwashers (flight-type warewashers) or as rack-conveyor dishwashers (rack-conveyor warewashers). In contrast to box-type dishwashers, in which the washware to be cleaned remains stationary in the machine during the cleaning process, in the case of conveyor dishwashers, the washware is conveyed through various treatment zones of the conveyor dishwasher.

In conveyor dishwashers, the washware, for example dishes, pots, glasses, cutlery and other utensils to be cleaned, is conveyed through several treatment zones, for example prewash zone(s), main wash zone(s), pump final rinse zone(s), fresh water final rinse zone(s), and drying zone(s). For conveying washware through the conveyor dishwasher in a conveying direction, use is made of a conveyor apparatus, which generally has compartments for holding washware. In a flight-type dishwasher, the compartments can be formed by supporting fingers on a conveyor belt of the conveyor apparatus. In rack-conveyor dishwashers, dish racks, in which compartments can be formed for receiving the washware to be treated, serve as the conveyor apparatus. It is conceivable here for the dish racks to be conveyed through the rack-conveyor dishwasher by a conveying device.

In the prewash zone (pre-clearing) of the conveyor dishwasher, loosely adhering dirt is removed from the washware to be treated. To this end, wash liquid is drawn in by a pump (prewash pump) from a storage tank associated with this treatment zone and is sprayed with the aid of suitable spray nozzles onto the washware to be cleaned. Subsequently, the wash liquid flows back into the storage tank again and is drawn in again there by the prewash pump, which is embodied as a circulation pump, and introduced into the circulation circuit. Usually, the storage tank is covered by screens, in order to keep relatively large dirt particles out of the rinse liquid.

In the at least one main wash zone, which is downstream of the prewash zone as seen in the conveying direction of the washware, dirt particles still adhering to the washware to be treated are removed from the washware with the aid of a usually alkaline wash liquid. To this end, the generally heated wash liquid is drawn in by a wash pump embodied as a circulation pump from the wash tank associated with the treatment zone and is sprayed over the washware with the aid of suitable positioned and oriented wash nozzles. Subsequently, the wash liquid flows back into the wash tank again and is drawn in again by the wash pump embodied as a circulation pump. Here too, the storage tank (wash tank) is usually covered by screens, in order in this way to keep relatively large dirt particles out of the wash liquid.

The at least one main wash zone is followed, as seen in the conveying direction of the washware, by at least one final rinse zone, in which generally heated fresh water is sprayed onto the washware, in order to rinse wash liquid still adhering to the surface of the washware and, if necessary, any remaining residues of dirt off the washware. If required, a rinse aid chemical can be added to the (hot) fresh water sprayed in the at least one final rinse zone.

The water circuit of modern conveyor dishwashers (multi-tank conveyor dishwashers) generally operates on the principle of the cascading overflow. Here, the fresh water sprayed in the at least one final rinse zone of the conveyor dishwasher is collected in a final rinse tank associated with the at least one final rinse zone and runs first of all into a wash tank that is located lower down and—as seen in the conveying direction of the washware—is associated with the at least one main wash zone upstream of the at least one final rinse zone. Subsequently, the liquid sprayed in the at least one main wash zone and collected via the wash tank associated with the at least one main wash zone runs into a prewash tank, located even lower down, of at least one prewash zone. As mentioned above, this at least one prewash zone is optionally provided and—as seen in the conveying direction of the washware—is upstream of the at least one main wash zone.

In order to add the wash chemical (detergent) in a metered manner to the liquid to be sprayed in the at least one main wash zone, in conveyor dishwashers known from the prior art use is generally made of metering units with an integrated logic circuit. These metering units are not usually part of the actual conveyor dishwasher but are supplied and used separately from the conveyor dishwasher. To this end, it is conventional for the conveyor dishwashers to have a corresponding interface, via which the conveyor dishwasher can communicate with the integrated logic circuit of the metering units. Here, it is conventional for the conveyor dishwasher or a control device of the conveyor dishwasher to supply appropriate information about the operating state or the selected treatment program to the logic circuit of the metering units. On the basis of this information, the metering unit is then actuated as appropriate via the integrated logic circuit. This relates for example to the measuring of the conductance of the wash liquid, the setting of a particular speed of the metering pump belonging to the metering unit, etc. These functions are usually carried out by the logic circuit (control device) which is integrated in the metering units.

The present invention is based on the finding that the customary approach, in which the actual metered addition of the wash chemical to the wash liquid takes place via the logic circuit associated with the corresponding metering unit has certain drawbacks during operation of the conveyor dishwasher. In particular when the conveyor dishwasher is started up, i.e. when the individual tanks of the conveyor dishwasher, in particular the wash tanks, are filled up with liquid, it is not generally possible to prevent liquid layers with different concentrations of wash chemicals from forming in the wash tank. This in turn has the result that, in particular when the conveyor dishwasher is started up, precise metered addition of the liquid is not possible. This in turn results in too little or too much in the way of wash chemicals being metered to the wash liquid and in a non-optimal cleaning result on the part of the conveyor dishwasher.

SUMMARY

Accordingly, the present application is based on the object of specifying a conveyor dishwasher in which the metered addition of wash chemicals (detergent) can take place as precisely as possible, in order to avoid too much or too little thereof potentially being metered into the wash liquid.

Accordingly, the invention relates in particular to a conveyor dishwasher comprising at least one wash zone and at least one final rinse zone, wherein the at least one wash zone is designed to spray wash liquid, wherein the wash liquid is, at least proportionally, liquid which has already been used for final rinsing in the at least one final rinse zone and to which a wash chemical is added in a metered manner or is fresh water to which a wash chemical is added in a metered manner, and wherein the conveyor dishwasher has a metering pump for adding the wash chemical in a metered manner to the liquid to be sprayed in the at least one wash zone. The invention provides in particular that a controller is associated with the conveyor dishwasher in order to actuate the metering pump and, in particular, a wash pump which is associated with the at least one wash zone and/or a final rinse pump which is associated with the at least one final rinse zone.

In other words, the invention provides in particular for the logic circuit usually integrated in the metering units to be shifted into the controller of the conveyor dishwasher, such that, for metering wash chemicals, conventional metering pumps without a controller and logic circuit can be used.

This not only provides a considerable cost advantage in the case of the metering pumps, but also optimizes the addition of the wash chemical in a metered manner to the wash liquid. Specifically, with the aid of the solution according to the invention, it is possible to effectively prevent, in particular when the conveyor dishwasher is started up, liquid layering in the at least one wash tank of the wash zone having the effect of too much or too little in the way of wash chemicals being added in a metered manner. Rather, the metered addition of the wash chemical takes place only via the controller of the conveyor dishwasher, such that, at any time, the optimum quantity of wash chemical can be determined and added in a metered manner. This effectively prevents over- or undertreatment of the washware to be treated in the conveyor dishwasher. At the same time, consumption of resources (in this case: in particular wash chemicals) can also be optimized.

According to one development of the conveyor dishwasher according to the invention, a sensor system is further provided in order to detect a concentration of wash chemical in the wash liquid to be sprayed in the at least one wash zone. The controller which is associated with the conveyor dishwasher is in this case designed in particular to actuate the metering pump of the conveyor dishwasher depending on the detected concentration of wash chemical.

In other words, in contrast to conventional solutions known from the prior art, in which the conveyor dishwasher is not equipped with a metering pump and the metering pump is subsequently installed in the form of a metering unit with an integrated logic circuit, according to this development, the sensor system associated with the conveyor dishwasher can detect the wash chemical concentration in particular in real time, and detects in particular the quantity of wash chemicals actually added in a metered manner to the wash liquid per unit time, and actuates the metering pump accordingly.

In a conceivable embodiment of the conveyor dishwasher according to the invention, the controller which is associated with the conveyor dishwasher is designed to set at least some of the parameters which characterize the treatment of washware in the at least one wash zone. This at least one parameter which characterizes the treatment of washware in the at least one wash zone is for example the conveying speed at which the washware is conveyed through the at least one wash zone, a quantity of wash liquid to be sprayed in the at least one wash zone per unit time, and/or the temperature of the wash liquid. According to the invention, the controller which is associated with the conveyor dishwasher is further designed to set the metering pump depending on at least one parameter which characterizes the treatment of washware in the at least one wash zone.

Further advantageous developments of the conveyor dishwasher according to the invention are specified in the dependent claims.

The invention also relates to a method for operating a conveyor dishwasher, in which, with one and the same controller, not only a metering pump for adding a wash chemical in a metered manner to the liquid to be sprayed in the at least one wash zone of the conveyor dishwasher but also in particular a wash pump which is associated with the at least one wash zone and/or a final rinse pump which is associated with the at least one final rinse zone are actuated.

Since, in the solution according to the invention, all the functions of the conveyor dishwasher, including the metered addition of the wash chemical, take place with one and the same controller, i.e. with the controller associated with the conveyor dishwasher, the conveyor dishwasher is suitable in particular also for remote monitoring, in which all the parameters for operating the conveyor dishwasher can be set and controlled away from the conveyor dishwasher itself.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following text, the invention is described on the basis of a preferred embodiment as an example with reference to the accompanying drawing.

In the drawing:

FIG. 1 shows a schematic view in longitudinal section of a conveyor dishwasher according to the invention.

DETAILED DESCRIPTION

FIG. 1 shows a conveyor dishwasher 2 comprising a conveyor apparatus 4 for conveying washware (not illustrated) through the conveyor dishwasher 2 in a conveying direction 8. The conveyor dishwasher 2 has at least one wash zone, for example as illustrated in FIG. 1, a prewash zone 12, and a main wash zone 14, which is arranged downstream of the prewash zone 12 as seen in the conveying direction 8.

As seen in the conveying direction 8, a postwash zone 16 (or pump final rinse zone) is arranged downstream of the at least one wash zone 12, 14, and at least one final rinse zone (or fresh water final rinse zone), for example as illustrated only one final rinse zone 18, is arranged downstream of the postwash zone 16. In the conveyor dishwasher 2 illustrated in FIG. 1, the final rinse zone 18 is followed in the conveying direction 8 of the washware by a drying zone 40. The respective zones 12, 14, 16, 18, 40 of the conveyor dishwasher 2 can be separated from one another via separating curtains 47. In the embodiment illustrated in FIG. 1, the inlet tunnel 10 itself is also separated from the inlet 11 via a separating curtain 47. As a result of the provision of the separating curtains 47, overspraying of wash liquid and final rinse liquid and the escape of vapors from the conveyor dishwasher 2 are prevented.

Said treatment zones 12, 14, 16, 18 of the conveyor dishwasher 2 have associated spray nozzles 20, 22, 24, 26, 28, 30. These spray nozzles 20, 22, 24, 26, 28, 30 serve to spray liquid onto the washware when the latter is conveyed through the respective treatment zones 12, 14, 16, 18 by the conveyor apparatus 4. The individual spray systems of the treatment zones 12, 14, 16, 18 ensure that the washware to be treated is spray-washed from the top side and from the underside.

In the conveyor dishwasher 2 schematically illustrated in FIG. 1, the final rinse zone 18 has, however, not only downwardly directed upper spray nozzles 20 and upwardly directed lower spray nozzles 22 but also transversely directed lateral spray nozzles 24 on each side of the conveyor apparatus 4. The use of lateral spray nozzles 24 allows targeted spraying of the washware surfaces (dish surfaces) with final rinse liquid even in shaded zones. Precisely in the case of a fully loaded conveyor system, i.e. with the dish rack loaded with plates located one against another, the use of lateral spray nozzles 24 in the final rinse zone 18 has a clear advantage with regard to the final rinse result (effective rinsing of detergent residues from dish surfaces even in shaded zones) compared with systems in which only upper and lower spray nozzles 20, 22 and no transversely directed lateral spray nozzles 24 are provided in the first rinse zone 18.

The postwash zone 16, main wash zone 14 and prewash zone 12 further have associated tanks (postwash tank 32, main wash tank 34, prewash tank 36) for receiving sprayed liquid and/or for providing liquid for the spray nozzles 26, 28, 30 of the respective treatment zones 14, 16, 18.

As already indicated, in the conveyor dishwasher 2 illustrated in FIG. 1, final rinse liquid, which is made up of fresh water with rinse aid added in a metered manner, is sprayed onto the washware (not illustrated) via the spray nozzles 20, 22, 24 of the final rinse zone 18, which are arranged above and below the conveyor apparatus 4 and laterally. Some of the sprayed final rinse liquid is conveyed from treatment zone to treatment zone via a cascade system counter to the conveying direction 8 of the washware. The rest of the final rinse liquid sprayed in the final rinse zone 18 is conducted via a valve V1 and a bypass line 38 directly into the prewash tank 36 which is associated with the prewash zone 12.

In the cascade system, the final rinse liquid sprayed by the final rinse nozzles 20, 22, 24 flows under gravity from the final rinse zone 18 into the postwash tank 32 which is associated with the postwash zone 16. The final rinse liquid collected by the postwash tank 32 and sprayed in the final rinse zone 18 is subsequently delivered with the aid of a postwash pump 45 to the spray nozzles (postwash nozzles 26) of the postwash zone 16.

In the postwash zone 16, wash liquid is rinsed off the washware. The liquid (postwash liquid) that arises in the process flows under gravity into the main wash tank 34 which is associated with the main wash zone 14. Preferably, a drainage element 39, for example a drainage floor or a guide plate, is provided for this purpose, which guides the postwash liquid sprayed by the postwash nozzles 26 into the main wash tank 34. According to another embodiment (not shown), the drainage element 39 can be dispensed with when the main wash tank 34 extends to beneath the postwash nozzles 26 of the postwash zone 16.

The liquid received by the main wash tank 34 of the main wash zone 14 is usually provided with a wash chemical in the form of a detergent and sprayed onto the washware with the aid of a main wash pump 35 via the spray nozzles (main wash nozzles 28) of the main wash zone 14. The wash liquid sprayed by the main wash nozzles 28 flows back into the main wash tank 34 under gravity.

The main wash tank 34 is fluidically connected to the prewash tank 36, which is associated with the prewash zone 12, via an overflow line 37. Via this overflow line 37, the wash liquid sprayed in the main wash zone 14 passes into the prewash tank 36 when enough wash liquid has been received in the main wash tank 34.

The liquid received in the prewash tank 36 of the prewash zone 12 is subsequently sprayed onto the washware with the aid of a prewash pump 33 via the spray nozzles (prewash nozzles 30) of the prewash zone 12, in order to remove coarse soiling from the washware. The wash liquid sprayed with the prewash nozzles 30 flows back into the prewash tank 36 under gravity.

The prewash tank 36 is provided with an overflow line 31, which serves to supply the excess quantity of liquid to a wastewater system when a liquid level in the prewash tank 36 is exceeded.

As already indicated, the liquid sprayed in the main wash zone 14 and in the prewash zone 12 contains a wash chemical in the form of a detergent. This wash chemical is added in a metered manner as required to the liquid received in the main wash tank 34 of the main wash zone 14 with the aid of a detergent metering apparatus.

The detergent metering apparatus has a corresponding metering pump 51, the suction side of which is connected in terms of flow to a reservoir 52 for wash chemicals. On the pressure side, the metering pump 51 is connected in terms of flow to the main wash tank 34.

As described in more detail in the following text, the metering pump 51 of the detergent metering apparatus is embodied preferably as an actuable metering pump 51. To this end, the metering pump 51 is connected to the control apparatus 50 of the conveyor dishwasher 2 via a control bus or similar (wired or wireless) control line.

As mentioned above, the final rinse zone 18 is followed in the conveying direction 8 by the drying zone 40. In the drying zone 40, the washware is dried with dry and heated air, in order to blow or dry off the moisture present on the washware. In order to keep the moisture content of the air in a range favorable for drying, it is conceivable, for example, to feed ambient air to the drying zone 40 from the outside via an opening, for instance through the outlet opening for the washware.

The hot and moist air in the drying zone 40 is subsequently extracted from the drying zone 40 for example with the aid of a fan 41 via a further opening. In this case, it is advantageous for the waste air stream from the drying zone 40 to pass through a device 42 for heat recovery, in which for example a condenser can be provided. The device 42 for heat recovery serves to recover at least a part of the thermal energy contained in the waste air.

If, before the conveyor dishwasher 2 is started for the first time, the tanks which are associated with the wash zones 12, 14 and 16 (prewash tank 36, main wash tank 34, postwash tank 32) are empty or only insufficiently filled, they first of all have to be filled via a fresh water line 90 and/or by final rinse liquid being sprayed in the final rinse zone 18. The fresh water line 90 is connectable to a fresh water supply system via an actuable valve V3. The quantity of wash liquid available in the main wash zone 14 and in the prewash zone 12 can be monitored with the aid of a level sensor provided in the main wash tank 34 and with the aid of a level sensor provided in the prewash tank 36, respectively, and signaled to a control apparatus 50.

The final rinse zone 18 can—as illustrated in FIG. 1—have an associated fresh water container 30 for the interim storage of at least some of the fresh water intended for final rinsing. The fresh water container 30 is provided on one side with a fresh water connection which is connectable to a fresh water supply system via an actuable fresh water supply valve V2, and is connected on the other side to the suction side of a final rinse pump 43. Of course, however, it is also conceivable to dispense with a fresh water container 30 for the interim storage of at least some of the fresh water provided for final rinsing, and to connect the fresh water supply valve V2 directly to the suction side of the final rinse pump 43.

The pressure side of the final rinse pump 43 is connected via a line system to a boiler 9. In this case, the line system is embodied such that the liquid delivered by the final rinse pump 43 to the spray nozzles 20, 22, 24 of the final rinse zone 18 first of all passes through the device 42 for heat recovery before it reaches the boiler 9. In this way, it is possible to use at least some of the thermal energy of the discharged waste air to heat the liquid fed to the spray nozzles 20, 22, 24 of the final rinse zone 18.

Rinse aid is added in a metered manner with the aid of a rinse aid metering apparatus to the fresh water fed to the final rinse pump 43 either directly from the fresh water supply valve V2 or from the fresh water container 30. The rinse aid metering apparatus has a (rinse aid) metering pump 57 and a rinse aid reservoir 58. Particularly preferably, the rinse aid metering pump 57 is arranged such that the metered addition of rinse aid to the fresh water takes place at a position in which the fresh water has not yet been heated. Tests have shown that much better and more uniform mixing of the rinse aid with the fresh water occurs when the rinse aid is added in a metered manner to fresh water that has not been heated. Specifically, rinse aid should be added in a metered manner into fresh water which is at a temperature of less than 40° C., and preferably less than 30° C. Consequently, in the embodiment of the conveyor dishwasher 2 illustrated in FIG. 1, the metered addition of rinse aid takes place between the final rinse pump 43 and the boiler 9 or the device 42 for heat recovery. To this end, a feed line that leads into the line system between the final rinse pump 43 and the device 42 for heat recovery is provided, said feed line being connectable to the rinse aid reservoir 58 via the metering pump 57.

Like the metering pump 51 of the detergent metering apparatus, the rinse aid metering pump 57 is connected to the control apparatus 50 of the conveyor dishwasher 2 preferably via a suitable control bus, such that the rinse aid metering pump 57 can also be actuated appropriately via the control apparatus 50.

In the conveyor dishwasher 2 illustrated in FIG. 1, the abovementioned control apparatus 50 is only schematically indicated. The control apparatus 50 is configured to automatically set a quantity of final rinse liquid to be sprayed per unit time in the final rinse zone 18 and/or to automatically set a quantity of wash liquid to be sprayed per unit time in the main wash zone 14. Preferably, the control apparatus 50 is designed to actuate the different actuable components of the conveyor dishwasher 2, for instance the respective pumps and valves, on the basis of a predefined or definable program sequence, in order in this way to be able to set the process parameters in the individual treatment zones 12, 14, 16, 18 of the conveyor dishwasher 2, and in particular the process parameters in the final rinse zone 18 and/or in the main wash zone 14.

However, the control apparatus 50 of the conveyor dishwasher 2 is in particular also configured to actuate the metering pump 51 of the detergent metering apparatus in a suitable manner in order to add a wash chemical in a metered manner as required to the liquid received in the main wash tank 34. Advantageously, the control apparatus 50 is also configured to actuate the rinse aid metering pump 57 in an appropriate manner in order to add rinse aid in a metered manner to the fresh water provided for final rinsing.

In the conveyor dishwasher 2 schematically illustrated in FIG. 1, the control apparatus 50 serves in particular to appropriately actuate the wash pump 35 which is associated with the main wash zone 14 and/or the pump 45 which is associated with the pump final rinse zone or postwash zone 16.

It is also preferred for the control apparatus 50 to be used to be able to set the conveying speed at which the washware is conveyed in the conveying direction 8 through the respective treatment zones 12, 14, 16, 18.

According to embodiments of the invention, with the aid of the control apparatus 50, the quantity of final rinse liquid injected per unit time in the final rinse zone 18 and/or the quantity of wash liquid injected per unit time in the main wash zone 14 is changed automatically depending on the conveying speed at which the washware is conveyed at least through the final rinse zone 18 or the main wash zone 14, and/or depending on the type of washware conveyed through the at least one final rinse zone 18 or the main wash zone 14.

In the conveyor dishwasher 2 illustrated in FIG. 1, the control apparatus 50 can be configured to selectively change the quantity of final rinse liquid and/or quantity of wash liquid injected per unit time automatically depending on the type of washware conveyed through the corresponding zone 18, 14 or depending on the conveying speed. However, in principle, it is also conceivable for the control apparatus 50 to be embodied to change the quantity of final rinse liquid and/or quantity of wash liquid injected per unit time only depending on the type of washware conveyed through the corresponding treatment zone, or only depending on the conveying speed.

In order to sense the type of washware to be treated in the conveyor dishwasher 2, the conveyor dishwasher 2 illustrated in FIG. 1 has a washware detector apparatus 53. The expression “washware detector apparatus” used herein should be understood as meaning any detection apparatus which is designed to sense or determine the type of washware to be treated in the conveyor dishwasher 2. It is conceivable for the washware detector apparatus 53 to have at least one detector device with which the size and/or the shape and/or the material of the washware to be treated in the conveyor dishwasher 2 can be sensed. In one possible embodiment of the washware detector apparatus 53, the latter comprises at least one preferably optically, inductively or capacitively operating detector device, such that, in order to identify the type of washware, the size, the shape and/or the material of the washware can be sensed. However, it is also possible for other detector types to be used as the detector device, for example inductively operating proximity sensors, light scanners, light curtains, laser scanners, 3D lasers, cameras, rotary coders etc.

As illustrated in FIG. 1, the washware detector apparatus 53 is arranged preferably at the inlet 11 of the conveyor dishwasher 2, in order that the type of washware to be fed into the individual treatment zones 12, 14, 16, 18, 40 of the conveyor dishwasher 2 can be sensed. However, it would of course also be conceivable to arrange the washware detector apparatus 53 inside the conveyor dishwasher 2. What is essential is that the washware detector apparatus 51 is arranged at least before the inlet into the final rinse zone 18.

The control apparatus 50 is connected to the washware detector apparatus 53 via a suitable communications connection, in order to continuously check, or to check at predefined times or events, the type of washware fed to the conveyor dishwasher 2 and sensed by the washware detector apparatus 53.

In the embodiment of a conveyor dishwasher 2 according to the invention that is illustrated in FIG. 1, the control apparatus 50 is designed to automatically identify the washware to be treated on the basis of the washware type sensed by the washware detector apparatus 53. Preferably, the control apparatus 50 can automatically identify at least the following washware:

plates made of porcelain or a porcelain-like material;

cups made of porcelain or a porcelain-like material, glass or a glass-like material;

bowls made of porcelain or a porcelain-like material, glass or a glass-like material;

trays or tray-like articles made of a plastics material;

containers, in particular food-grade containers, made of metal, in particular of stainless steel;

pots made of metal, in particular of stainless steel;

pans made of metal, in particular of stainless steel;

cutlery or items of cutlery made of metal, in particular of stainless steel; and

drinking glasses made of glass or a glass-like material.

If the control apparatus 50 does not identify the washware from the type of washware sensed by the washware detector apparatus 53, the washware in question is identified as “other washware”.

The solution according to the invention is characterized in particular in that the control apparatus 50 of the conveyor dishwasher 2 is configured to set the corresponding process parameters of the selected treatment program depending on a treatment program selected by the user of the conveyor dishwasher 2, and at the same time, depending thereon, also to appropriately actuate at least the metering pump 51 of the detergent metering apparatus. With the actuation of the metering pump 51 of the detergent metering apparatus, it is in particular also possible to take a wash chemical concentration in the wash liquid or liquid received in the main wash tank 34 into consideration at the same time.

For this purpose, a corresponding sensor system 54 is provided, which is configured to sense a wash chemical concentration in the wash liquid to be sprayed in the main wash zone 14. The control apparatus 50 which is associated with the conveyor dishwasher 2 is in this case configured to actuate the metering pump 51 of the detergent metering apparatus in particular also depending on the sensed wash chemical concentration. It is conceivable in this connection in particular for the metering pump 51 of the detergent metering apparatus to be actuated only depending on the sensed wash chemical concentration. Alternatively, however, it is also conceivable if, when the metering pump 51 of the detergent metering apparatus is actuated, process parameters of a selected treatment program of the conveyor dishwasher 2 are also taken into consideration at the same time.

Suitable process parameters are in particular the quantity of wash liquid sprayed in the main wash zone 14 per unit time, the quantity of final rinse liquid sprayed in the final rinse zone 18 per unit time, and/or a degree of soiling of the wash liquid to be sprayed in the main wash zone 14.

In this connection, it is advantageous if the main wash zone 14 also has an associated corresponding sensor system, with the aid of which the degree of soiling in particular of the wash liquid received in the main wash tank 34 can be sensed. A turbidity sensor or a sensor for sensing a conductivity value of the liquid received in the main wash tank 34 is suitable, for example, as the sensor system.

In general, the control apparatus 50 which is associated with the conveyor dishwasher 2 is configured in particular to set at least some of the parameters that characterize the treatment of washware in the main wash zone 14. This relates—as already mentioned—for example to a quantity of wash liquid sprayed in the main wash zone 14 per unit time, but also conceivable is the conveying speed at which the washware is conveyed through the main wash zone 14, and/or a temperature of the wash liquid sprayed in the main wash zone 14, and/or the degree of soiling of the wash liquid to be sprayed in the main wash zone 14, and/or a wash chemical concentration of the wash liquid to be sprayed in the main wash zone 14.

In particular, the control apparatus 50 which is associated with the conveyor dishwasher 2 is also configured to set the metering pump 51 of the detergent metering apparatus depending on at least one parameter that characterizes the treatment of washware in the main wash zone 14.

According to embodiments of the conveyor dishwasher according to the invention, the control apparatus 50 which is associated with the conveyor dishwasher 2 is configured in particular, depending on a program cycle selected for the treatment of washware and/or depending on the type of washware to be treated and/or depending on a degree of soiling of the washware to be treated, to appropriately actuate the metering pump 51 of the detergent metering apparatus. It is conceivable in this connection for example if the control apparatus 50 which is associated with the conveyor dishwasher 2 is configured to actuate the metering pump 51 of the detergent metering apparatus such that continuous basic metering takes place.

The control apparatus 50 of the conveyor dishwasher 2 can, according to embodiments, be configured to output to the metering pump 51 of the detergent metering apparatus all the commands that are necessary for the metered addition of the wash chemical, preferably via a corresponding control bus. Alternatively or additionally, the control apparatus 50 can be configured to sense all the parameters that are necessary for defining a quantity of wash chemical to be added in a metered manner per unit time and/or all the parameters that are necessary for defining the time and/or the duration of a metered addition of the wash chemical, and, if appropriate, to evaluate said parameters accordingly.

In this connection, it is appropriate for a data transmission system, in particular a wireless data transmission system, to be provided in order to transmit control signals that are necessary for controlling the metering pump 51 of the detergent metering apparatus from the control apparatus 50 which is associated with the conveyor dishwasher 2 to the metering pump 51.

Aspects of the invention include A-O below.

A. A conveyor dishwasher (2) comprising at least one wash zone (14) and at least one final rinse zone (16, 18), wherein the at least one wash zone (14) is designed to spray wash liquid, wherein the wash liquid is, at least proportionally, liquid which has already been used for final rinsing in the at least one final rinse zone (16, 18) and to which a wash chemical is added in a metered manner or is fresh water to which a wash chemical is added in a metered manner, wherein the conveyor dishwasher (2) has a metering pump (51) for adding the wash chemical in a metered manner to the liquid to be sprayed in the at least one wash zone (14), and wherein a controller (50) is associated with the conveyor dishwasher (2) in order to actuate the metering pump (51) and, in particular, a wash pump (35) which is associated with the at least one wash zone (14) and/or a final rinse pump (45) which is associated with the at least one final rinse zone (16, 18).

B. The conveyor dishwasher (2) of A, wherein a sensor system (54) is further provided in order to detect a concentration of wash chemical in the wash liquid to be sprayed in the at least one wash zone (14), wherein the controller (50) which is associated with the conveyor dishwasher (2) is designed to actuate the metering pump (51) depending on the detected concentration of wash chemical.

C. The conveyor dishwasher (2) of A or B, wherein the controller (50) which is associated with the conveyor dishwasher (2) is designed to set at least some of the parameters which characterize the treatment of washware in the at least one wash zone (14), and wherein the controller (50) which is associated with the conveyor dishwasher (2) is further designed to set the metering pump (51) depending on at least one parameter which characterizes the treatment of washware in the at least one wash zone (14).

D. The conveyor dishwasher (2) of C, wherein the at least one parameter which characterizes the treatment of washware in the at least one wash zone (14) is a conveying rate at which washware is conveyed through the at least one wash zone (14), a quantity of wash liquid which is sprayed in the at least one wash zone (14) per unit time and/or a temperature of the wash liquid.

E. The conveyor dishwasher (2) of any one of A-D, wherein the controller (50) which is associated with the conveyor dishwasher (2) is designed to correspondingly actuate the metering pump (51) depending on a program cycle which is selected for treating the washware and/or depending on the type of washware to be treated and/or depending on a degree of soiling of the washware to be treated.

F. The conveyor dishwasher (2) of any one of A-E, wherein the controller (50) which is associated with the conveyor dishwasher (2) is designed to actuate the metering pump (51) in such a way that continuous basic metering in the wash liquid is performed over time.

G. The conveyor dishwasher (2) of any one of A-F, wherein the controller (50) which is associated with the conveyor dishwasher (2) is designed to submit to the metering pump (51) all commands which are necessary for adding the wash chemical in a metered manner and/or to detect and possibly correspondingly to evaluate all parameters which are necessary for defining a quantity of the wash chemical to be added in a metered manner per unit time and/or all parameters which are necessary for defining the time and/or the duration of an operation for adding the wash chemical in a metered manner.

H. The conveyor dishwasher (2) of any one of A-G, wherein a data transmission system is provided in order to transmit to the metering pump (51) control signals, which are required for controlling the metering pump (51), from the controller (50) which is associated with the conveyor dishwasher (2).

I. The conveyor dishwasher (2) of any one of A-H, wherein, in the at least one final rinse zone (16, 18), final rinse liquid, which is made up of fresh water and possibly rinse aid which has been added in a metered manner or which is made up of liquid which has already been used for final rinsing and possibly rinse aid which has been added in a metered manner, is distributed, in particular injected or sprayed, onto washware to be treated in the at least one final rinse zone (16, 18), and wherein a metering pump (57) which can be actuated by means of the controller (50) which is associated with the conveyor dishwasher (2) is provided in order to add rinse aid in a metered manner as necessary to the liquid to be distributed in the at least one final rinse zone (16, 18).

J. The conveyor dishwasher (2) of I, wherein the controller (50) which is associated with the conveyor dishwasher (2) is designed to automatically set a quantity of final rinse liquid to be distributed in the at least one final rinse zone (16, 18) per unit time, specifically depending on a conveying rate at which washware is conveyed through the at least one final rinse zone (16, 18), and/or depending on the type of washware transported through the at least one final rinse zone (16, 18).

K. The conveyor dishwasher (2) any one of A-J, wherein a washware detector apparatus (53) is provided, which washware detector apparatus is designed to detect the type of washware to be treated, and wherein the controller (50) which is associated with the conveyor dishwasher (2) is designed to automatically set a quantity of wash liquid injected in the at least one wash zone (14) per unit time and/or to automatically set a quantity of final rinse liquid injected in the at least one final rinse zone (16, 18) per unit time depending on the detected type of washware to be treated.

L. The conveyor dishwasher (2) of K, wherein the controller (50) is designed to automatically set the conveying rate at which the washware is conveyed through the at least one wash zone (14) and final rinse zone (16, 18) depending on the detected type of washware to be treated.

M. The conveyor dishwasher (2) of K or L, wherein the washware detector apparatus (53) has at least one optically operating detector device and/or at least one inductively or capacitively operating detector device and is designed to automatically identify glasses or racks for glasses and/or to automatically identify cutlery or racks for cutlery.

N. The conveyor dishwasher (2) of any one of A-M, wherein the wash pump (35) which is associated with the at least one wash zone (14) is preferably a rotation speed-controlled pump, and/or wherein the final rinse pump (45) which is associated with the at least one final rinse zone (16, 18) is preferably a rotation speed-controlled pump.

O. A method for operating a conveyor dishwasher (2), in particular a conveyor dishwasher (2) according to any one of A-N, wherein, with the aid of a controller (50) which is associated with the conveyor dishwasher (2), at least some of the parameters which characterize the treatment of washware in at least one wash zone (14) of the conveyor dishwasher (2) are set, and wherein furthermore a metering pump (51) for metering a wash chemical into the liquid to be sprayed in the at least one wash zone (14) as desired is actuated with the aid of the controller (50) which is associated with the conveyor dishwasher (2), specifically particularly depending on at least one parameter which characterizes the treatment of washware in the at least one wash zone (14).

The invention is not limited to the embodiment shown by way of example in the drawing, but is the result of overall consideration of the claims and of the description of the exemplary embodiment by a person skilled in the art. 

What is claimed is:
 1. A conveyor dishwasher comprising: at least one wash zone and at least one final rinse zone, wherein the at least one wash zone is designed to spray wash liquid, wherein the wash liquid is, at least proportionally, liquid which has already been used for final rinsing in the at least one final rinse zone and to which a wash chemical is added in a metered manner or is fresh water to which a wash chemical is added in a metered manner, wherein the conveyor dishwasher has a metering pump for adding the wash chemical in a metered manner to the liquid to be sprayed in the at least one wash zone, and wherein a controller is associated with the conveyor dishwasher in order to actuate both (i) the metering pump and (ii) a wash pump which is associated with the at least one wash zone and/or a final rinse pump which is associated with the at least one final rinse zone.
 2. The conveyor dishwasher as claimed in claim 1, wherein a sensor system is further provided in order to detect a concentration of wash chemical in the wash liquid to be sprayed in the at least one wash zone, wherein the controller which is associated with the conveyor dishwasher is designed to actuate the metering pump depending on the detected concentration of wash chemical.
 3. The conveyor dishwasher as claimed in claim 2, wherein the controller which is associated with the conveyor dishwasher is designed to set at least some of the parameters which characterize the treatment of washware in the at least one wash zone, and wherein the controller which is associated with the conveyor dishwasher is further designed to set the metering pump depending on at least one parameter which characterizes the treatment of washware in the at least one wash zone.
 4. The conveyor dishwasher as claimed in claim 3, wherein the at least one parameter which characterizes the treatment of washware in the at least one wash zone is a conveying rate at which washware is conveyed through the at least one wash zone, a quantity of wash liquid which is sprayed in the at least one wash zone per unit time and/or a temperature of the wash liquid.
 5. The conveyor dishwasher as claimed in claim 1, wherein the controller which is associated with the conveyor dishwasher is designed to correspondingly actuate the metering pump depending on a program cycle which is selected for treating the washware and/or depending on the type of washware to be treated and/or depending on a degree of soiling of the washware to be treated.
 6. The conveyor dishwasher as claimed in claim 1, wherein the controller which is associated with the conveyor dishwasher is designed to actuate the metering pump in such a way that continuous basic metering in the wash liquid is performed over time.
 7. The conveyor dishwasher as claimed in claim 1, wherein the controller which is associated with the conveyor dishwasher is designed to submit to the metering pump all commands which are necessary for adding the wash chemical in a metered manner and/or to detect and possibly correspondingly to evaluate all parameters which are necessary for defining a quantity of the wash chemical to be added in a metered manner per unit time and/or all parameters which are necessary for defining the time and/or the duration of an operation for adding the wash chemical in a metered manner.
 8. The conveyor dishwasher as claimed in claim 1, wherein a data transmission system is provided in order to transmit to the metering pump control signals, which are required for controlling the metering pump, from the controller which is associated with the conveyor dishwasher.
 9. The conveyor dishwasher as claimed in claim 1, wherein, in the at least one final rinse zone, final rinse liquid, which is made up of fresh water and possibly rinse aid which has been added in a metered manner or which is made up of liquid which has already been used for final rinsing and possibly rinse aid which has been added in a metered manner, is injected or sprayed, onto washware to be treated in the at least one final rinse zone, and wherein a metering pump which can be actuated by means of the controller which is associated with the conveyor dishwasher is provided in order to add rinse aid in a metered manner as necessary to the liquid to be distributed in the at least one final rinse zone.
 10. The conveyor dishwasher as claimed in claim 9, wherein the controller which is associated with the conveyor dishwasher is designed to automatically set a quantity of final rinse liquid to be distributed in the at least one final rinse zone per unit time, specifically depending on a conveying rate at which washware is conveyed through the at least one final rinse zone, and/or depending on the type of washware transported through the at least one final rinse zone.
 11. The conveyor dishwasher as claimed in claim 1, wherein a washware detector apparatus is provided, which washware detector apparatus is designed to detect the type of washware to be treated, and wherein the controller which is associated with the conveyor dishwasher is designed to automatically set a quantity of wash liquid injected in the at least one wash zone per unit time and/or to automatically set a quantity of final rinse liquid injected in the at least one final rinse zone per unit time depending on the detected type of washware to be treated.
 12. The conveyor dishwasher as claimed in claim 11, wherein the controller is designed to automatically set the conveying rate at which the washware is conveyed through the at least one wash zone and final rinse zone depending on the detected type of washware to be treated.
 13. The conveyor dishwasher as claimed in claim 12, wherein the washware detector apparatus has at least one optically operating detector device and/or at least one inductively or capacitively operating detector device and is designed to automatically identify glasses or racks for glasses and/or to automatically identify cutlery or racks for cutlery.
 14. The conveyor dishwasher as claimed in claim 1, wherein the wash pump which is associated with the at least one wash zone is preferably a rotation speed-controlled pump, and/or wherein the final rinse pump which is associated with the at least one final rinse zone is preferably a rotation speed-controlled pump.
 15. A method for operating a conveyor dishwasher as claimed in claim 1, wherein, with the aid of a controller which is associated with the conveyor dishwasher, at least some of the parameters which characterize the treatment of washware in at least one wash zone of the conveyor dishwasher are set, and wherein furthermore a metering pump for metering a wash chemical into the liquid to be sprayed in the at least one wash zone as desired is actuated with the aid of the controller which is associated with the conveyor dishwasher, specifically particularly depending on at least one parameter which characterizes the treatment of washware in the at least one wash zone. 